a) The suggested route of administration for each vaccine is recommended by the manufacturer and is based on studies showing maximum safety and immunogenicity.
b) The presence or absence of an adjuvant is not a factor when considering vaccine administration.
c) For most infants younger than 12 months of age, the anterolateral thigh muscle is the preferred site because it has more muscle mass than the deltoid muscle.
d) The buttock generally should not be used for active immunization because of limited absorption from gluteal fat.
Answer: a, c and d are correct